1. Field of the Invention
The present invention relates to a lawn mower for use in a walking operator mode and a riding operator mode.
2. Description of the Related Art
A riding type lawn mower, as disclosed in U.S. Pat. No. 4,957,183, has an engine mounted on a front portion of a vehicle body, a driver's section disposed rearwardly, and a grass cutting unit underslung between front and rear wheels. The mower runs on the wheels driven respectively by hydraulic motors, and is steerable by turning the wheels up to about 90 degrees with a steering wheel disposed in the center and forwardly of a driver's seat.
The riding type lawn mower having the above construction is capable of a small, sharp turn with the center of turning moved to a position inwardly of a peripheral edge of the grass cutting unit. This turning capability provides the advantage of realizing an efficient grass cutting operation leaving no uncut patches. However, since the engine is mounted forwardly of the driver's section, the mower has an extensive fore and aft length. Consequently, the driver has difficulties in observing grass patches ahead of the mower during a grass cutting run. In addition, when boarding and alighting from the mower, the driver has the inconvenience of having to move through a narrow space between the driver's seat and steering wheel.
In the case of walking operator type lawn mower, one known example, as disclosed in U.S. Pat. No. 4,934,989, has a grass cutting unit mounted between caster type front wheels and engine-driven rear wheels, and control levers extending rearwardly for a walking operator to steer the mower. This lawn mower is easily controllable by operating transmission clutches provided for the rear wheels, respectively. It is possible to drive the mower along a complicated curve to engage in a grass cutting operation. However, when the mower is caused to run along a long straight line, the operator must follow the mower in a tedious walk. The walking operator type lawn mower has a low reputation for use in an operation involving such long straight walks.
As further examples, Applicants have disclosed lawn mowers for use in a walking mode as well as a riding mode, in U.S. patent applications Ser. No. 07/865,726 filed Apr. 8, 1992 and Ser. No. 07/874,647 filed Apr. 27, 1992. In each of these mowers, front control levers disposed adjacent a driver's seat and rear control levers arranged rearwardly of a vehicle body are operatively connected to transmissions for varying drive speeds of right and left rear wheels, respectively. The user may freely choose to use this type of lawn mower in the walking mode or in the riding mode. However, this type of lawn mower has the disadvantage of requiring a complicated link mechanism to allow the transmissions to be controlled both by the front control levers and by the rear control levers. As a further disadvantage, the rear control levers are obstructive when the mower is used in the riding mode, and the front control levers when the mower is used in the walking mode.